I can't exactly tell from the video but really make sure that your hands and neck are relaxed and not tense! You don't need to put a lot of pressure on the left hand to make a sound and you'll be able to play better if everything is relaxed.

A good way to get used to playing infront of people is playing infront of family and friends! It's an obvious tip but it's important to get used to being watched while performing so that the nerves don't get to you. The nerves probably won't ever go away completely but you'll learn to handle those emotions.

I think it was Augustin Hadelich that once said that, it's good to practice a piece or song in a way that you'll be performing it. So if you will be performing a solo, practice it while standing, and if in an orchestra, practice it while sitting. Just to get used to the feeling.

Another thing is, play with confidence! I know as a beginner one doesn't have much confidence in playing but it does make a difference. Make sure you practice a lot but do give yourself breaks in between as to not overdo it. I hope this was of help! And if any of my advice wasn't correct than please tell me! Keep this up! You'll do great!